Method and apparatus for detecting defects on wafers

Abstract

Methods and apparatuses for detecting particle defects on partially fabricated semiconductor wafers using chemical markers capable of binding to defects that are not detectable by laser diffractometry are provided herein.

1 . A method of detecting defects of a partially fabricated semiconductor wafer for semiconductor devices, the method comprising:
 exposing the partially fabricated semiconductor wafer to a first chemical marker capable of selectively binding to particle defects disposed on the partially fabricated semiconductor wafer surface, undetectable by laser diffractometry and having a first composition, the chemical marker comprising a component capable of detection when exposed to a stimulant;   after exposing the wafer to the chemical marker, exposing the partially fabricated semiconductor wafer to the stimulant to form detectable areas of the partially fabricated semiconductor wafer where the first chemical marker is selectively bound to the particle defects; and   detecting the detectable areas on the surface of the partially fabricated semiconductor wafer,   wherein the surface of the partially fabricated semiconductor wafer includes less than about 2000 defects.   
     
     
         2 . The method of  claim 1 , wherein the surface of the partially fabricated semiconductor wafer includes less than about 50 defects. 
     
     
         3 . (canceled) 
     
     
         4 . The method of  claim 1 , wherein the partially fabricated semiconductor wafer is exposed to the first chemical marker in an aqueous bath comprising the first chemical marker. 
     
     
         5 . The method of  claim 1 , wherein the diameter of the particle defects is less than about 20 nm. 
     
     
         6 . (canceled) 
     
     
         7 . The method of  claim 1 , further comprising exposing the partially fabricated semiconductor wafer to a second chemical marker selective to particle defects having a second composition to bind the second chemical marker to the particle defects having the second composition. 
     
     
         8 . The method of  claim 7 , wherein the first chemical marker emits a first spectral distribution of illumination when exposed to the stimulant, and wherein the second chemical marker emits a second spectral distribution of illumination different from the first spectral distribution of illumination when exposed to the simulant. 
     
     
         9 . The method of  claim 8 , wherein the first spectral distribution of illumination is a color in the visible spectrum and the second spectral distribution of illumination is another color in the visible spectrum. 
     
     
         10 . The method of  claim 7 , wherein exposing the partially fabricated semiconductor wafer to the first chemical marker and exposing the partially fabricated semiconductor wafer to the second chemical marker comprises immersing the partially fabricated semiconductor wafer in an aqueous bath comprising the first chemical marker and the second chemical marker. 
     
     
         11 . The method of  claim 7 , wherein exposing the partially fabricated semiconductor wafer to the first chemical marker and exposing the partially fabricated semiconductor wafer to the second chemical marker comprises delivering an aerosol spray of a solution comprising the first chemical marker and the second chemical marker to a chamber housing the partially fabricated semiconductor wafer. 
     
     
         12 . The method of  claim 1 , further comprising modifying a process recipe for fabricating the partially fabricated semiconductor wafer to reduce particle defects in the detectable areas of the partially fabricated semiconductor wafer. 
     
     
         13 - 16 . (canceled) 
     
     
         17 . An apparatus for detecting defects on a partially fabricated semiconductor wafer, the apparatus comprising:
 (a) a detection chamber comprising a wafer holder for holding the partially fabricated semiconductor wafer in the detection chamber;   (b) an inlet for delivering a chemical marker to the detection chamber;   (c) an illumination source for stimulating the chemical marker to emit light;   (d) a detector for detecting emissions of the chemical marker on the surface of the partially fabricated semiconductor wafer; and   (e) a controller for controlling operations of the apparatus, the controller comprising machine-readable instructions for:
 introducing the chemical marker to the detection chamber via the inlet; 
   removing excess chemical marker from the detection chamber after introducing the chemical marker to the detection chamber; and
 turning on the illumination source to illuminate the chemical marker. 
   
     
     
         18 . The apparatus of  claim 17 , further comprising a tracking device oriented for detecting the wafer surface while the wafer is held on the wafer holder; and a wafer imaging system comprising image analysis logic for detecting illuminated chemical markers on the wafer surface using properties of the illuminated chemical markers. 
     
     
         19 . The apparatus of  claim 18 , wherein the properties comprise a spectral distribution of illumination. 
     
     
         20 . The apparatus of  claim 18 , wherein the wafer imaging system further comprises a feedback mechanism for modifying process recipes in response to data collected from the tracking device. 
     
     
         21 . The apparatus of  claim 17 , wherein the properties comprise brightness. 
     
     
         22 . The apparatus of  claim 17 , further comprising a wafer transfer tool for inserting and removing a wafer from the detection chamber. 
     
     
         23 . The apparatus of  claim 22 , wherein the apparatus is integrated with a semiconductor device fabrication apparatus, the semiconductor device fabrication apparatus comprising one or more process chambers for processing semiconductor wafers and the wafer transfer tool. 
     
     
         24 . The apparatus of  claim 17 , wherein the inlet is capable of delivering an aqueous solution comprising the chemical marker to the detection chamber. 
     
     
         25 . The apparatus of  claim 17 , wherein the inlet is capable of delivering an aerosol spray of the chemical marker to the detection chamber to contact the wafer with the chemical marker, wherein the inlet is positioned over the top surface of the wafer. 
     
     
         26 . The apparatus of  claim 17 , wherein the detection chamber is capable of containing an aqueous bath comprising one or more chemical markers and the wafer holder is capable of immersing the wafer in the aqueous bath.